<?php

class LtDbSqlAdapterSqlite implements LtDbSqlAdapter
{
    public function setCharset($charset)
    {
        // return 'PRAGMA encoding = "' . $charset . '"';
        return '';
    }

    public function setSchema($schema)
    {
        return '';
    }

    public function beginTransaction()
    {
        return 'BEGIN TRANSACTION';
    }

    public function commit()
    {
        return 'COMMIT TRANSACTION';
    }

    public function rollBack()
    {
        return 'ROLLBACK TRANSACTION';
    }

    public function showSchemas($database)
    {
        //return "SHOW DATABASES";
        return '';
    }

    public function showTables($schema)
    {
        // 临时表及其索引不在 SQLITE_MASTER 表中而在 SQLITE_TEMP_MASTER 中出现
        return "SELECT name FROM sqlite_master WHERE type='table' UNION ALL SELECT name FROM sqlite_temp_master WHERE type='table' ORDER BY name";
    }

    public function showFields($table)
    {
        return "PRAGMA table_info('" . $table . "')";

    }

    public function limit($limit, $offset)
    {
        return " LIMIT $limit OFFSET $offset";
    }

    public function getSchemas($queryResult)
    {

    }

    public function getTables($queryResult)
    {
        return $queryResult;
    }

    public function getFields($queryResult)
    {
        $fields = array();
        foreach ($queryResult as $key => $value) {
            // 字段名
            $fields[$value['name']]['name'] = $value['name'];
            // 字段类型
            $fulltype = $value['type'];
            $size = null;
            $precision = null;
            $scale = null;

            if (preg_match('/^([^\(]+)\(\s*(\d+)\s*,\s*(\d+)\s*\)$/', $fulltype, $matches)) {
                $type = $matches[1];
                $precision = $matches[2];
                $scale = $matches[3]; // aka precision
            } elseif (preg_match('/^([^\(]+)\(\s*(\d+)\s*\)$/', $fulltype, $matches)) {
                $type = $matches[1];
                $size = $matches[2];
            } else {
                $type = $fulltype;
            }

            $fields[$value['name']]['type'] = $type;
            /**
             * not null is 99, null is 0
             */
            $fields[$value['name']]['notnull'] = (bool)($value['notnull'] != 0);
            $fields[$value['name']]['default'] = $value['dflt_value'];
            $fields[$value['name']]['primary'] = (bool)($value['pk'] == 1 && strtoupper($fulltype) == 'INTEGER');
        }
        return $fields;
    }

    public function detectQueryType($sql)
    {
        if (preg_match("/^\s*SELECT|^\s*PRAGMA/i", $sql)) {
            $ret = 'SELECT';
        } else if (preg_match("/^\s*INSERT/i", $sql)) {
            $ret = 'INSERT';
        } else if (preg_match("/^\s*UPDATE|^\s*DELETE|^\s*REPLACE/i", $sql)) {
            $ret = 'CHANGE_ROWS';
        } else if (preg_match("/^\s*USE|^\s*SET/i", $sql)) {
            $ret = 'SET_SESSION_VAR';
        } else {
            $ret = 'OTHER';
        }
        return $ret;
    }
}